Christian Raschner

An Overview of Recent Application of Medical Infrared Thermography in Sports Medicine in Austria

Medical infrared thermography (MIT) is used for analyzing physiological functions related to skin temperature. Technological advances have made MIT a reliable medical measurement tool. This paper provides an overview of MIT’s technical requirements and usefulness in sports medicine, with a special focus on overuse and traumatic knee injuries. Case studies are used to illustrate the clinical applicability and limitations of MIT. It is concluded that MIT is a non-invasive, non-radiating, low cost detection tool which should be applied for pre-scanning athletes in sports medicine.

Knee joint forces during downhill walking with hiking poles

The aim of this study was to determine external and internal loads on the knee joint during downhill walking with and without hiking poles. Kinematic, kinetic and electromyographic data were collected from eight males during downhill walking on a ramp declined at 25 degrees. Planar knee joint moments and forces were calculated using a quasi-static knee model. The results were analysed for an entire pole-cycle as well as differentiated between single and double support phases and between each step of a pole-cycle. Significant differences between downhill walking with and without hiking poles were observed for peak and average magnitudes of ground reaction force, knee joint moment, and tibiofemoral compressive and shear forces (12-25%). Similar reductions were found in patellofemoral compressive force, the quadriceps tendon force and the activity of the vastus lateralis; however, because of a high variability, these differences were not significant. The reductions seen during downhill walking with hiking poles compared with unsupported downhill walking were caused primarily by the forces applied to the hiking poles and by a change in posture to a more forward leaning position of the upper body, with the effect of reducing the knee moment arm.

Specific fitness training and testing in competitive sports.

Improvements of athletic capacity in high-performance sport are mainly achieved through an increase of the quality of training. In physical preparation, the quality of training can be improved by developing highly specific means of training. The aim of this paper is to present three examples of how highly specific means of fitness training of world class athletes can be developed. The first example presents a test profile of specific motor abilities of top class tennis players, the second one deals with the improvement of specific strength training methods for ski jumpers, and the third deals with the development of specific training devices of Alpine ski racers.

The relationship between ACL injuries and physical fitness in young competitive ski racers: a 10-year longitudinal study

Background Epidemiological studies have shown a high incidence of anterior cruciate ligament (ACL) injuries among competitive alpine skiers. Little is known regarding modifiable risk factors in young skiers. There are still uncertainties in gender-related risk factors. Objective The purpose of this study was to determine the relationship between ACL injuries and internal risk factors. Methods Retrospective data analyses were performed based on a group of 175 female and 195 male alpine ski racers between the ages of 14 and 19 years. The athletes underwent physical testing annually from 1996 to 2006. Z score transformations normalised the age groups. Multivariate binary logistic regressions were calculated for men and women separately to detect significant predictors of ACL ruptures. t Tests were computed to reveal the differences in test scores between injured and non-injured athletes. Results A total of 57 (15%) ACL injuries occurred. The female−male risk ratio (RR) was higher in females (2.3, 95% CI 1.3 to 4.2). Z scores for relative leg force, ratio of absolute core flexion to extension force, relative core strength and reactive strength index were predictive variables for men. Z scores of all of these predictive variables except relative leg force were higher in the non-injured group. The ratios of absolute flexion to extension force and absolute core strength were predictive covariates for women. Z scores for absolute core strength were higher in the non-injured group. Conclusions The risk of ACL injury was greater in female athletes. The findings suggest that core strength is a predominant critical factor for ACL injuries in young ski racers.

Preoperative proprioceptive training in patients with total knee arthroplasty

Proprioceptive deficiencies due to osteoarthritis and arthroplasty have been repeatedly reported. Proprioceptive training, which leads to an economisation of movements and supports energy-saving movement patterns, has become popular in athletes, but not in rehabilitation yet. The aim of this randomised phase IIb study was to evaluate whether preoperative proprioceptive training would influence postoperative balance and function in activities of daily life in patients undergoing total knee arthroplasty. Subjects with severe osteoarthritis of the knee scheduled for TKA were randomised to either a control group (CG) or a training group (TG). All patients were examined 6 weeks before and 6 weeks after TKA, patients of the TG also one day before surgery, i.e. after six weeks of preoperative proprioceptive training, in order to evaluate the influence of training without TKA. Evaluation included balance assessment using the Biodex Stability System, as well as measurements of gait speed and clinical outcome using the WOMAC and Knee Society Score. As opposed to the CG, stance stability improved significantly in the TG (Biodex OSI (p=0.045), APSI (p=0.029)) 6 weeks after TKA. There was a significant improvement in KSS, WOMAC pain and stiffness in both groups after TKA. Preoperative proprioceptive training in patients undergoing TKA resulted in improved standing balance, but no difference in clinical outcome was observed between the two groups.

The Application of Medical Infrared Thermography in Sports Medicine

Medical Infrared Thermography (MIT) is a non-radiating and contact-free technology to monitor physiological functions related to skin temperature control. The efficiency, safety and low cost of MIT make it a useful auxiliary tool for detecting and locating thermal abnormalities characterized by increases or decreases in skin surface temperature. It has been successfully utilized in the field of veterinary medicine to detect locomotion injuries in racehorses and to monitor their health status. However, research on human athletes with modern infrared sensor technology is more rare. Athletes are exposed to physical stress in training and during competition season. Overuse reactions and so-called “minor traumas” are very frequent; therefore, early detection is critical to avoid injuries. Research suggests that the most beneficial application of MIT is the screening of individuals for overuse injuries. In the following chapters, the use of MIT in clinical practice is presented with special focus on sports injuries and exercise-induced physiological functions. Case studies illustrate the clinical applicability.

Comparison of Physical Characteristics and Performance Among Elite Snowboarders

Platzer, H-P, Raschner, C, Patterson, C, Lembert, S. Comparison of physical characteristics and performance among elite snowboarders. J Strength Cond Res 23(5): 1427-1432, 2009-There are little scientific data regarding snowboarding and the physiological demands on snowboarders. The aim of this study was to assemble and evaluate a battery of tests for the snowboard disciplines parallel, snowboard cross (SBX), big air, and half-pipe (HP). Thirty-seven competitive snowboarders participated in the study and completed a test battery that comprised tests for aerobic capacity, balance, jumping, isokinetic core power, isokinetic leg power, isometric bench press, isometric bench pull, and a snowboard start simulator. The results showed that the battery of tests explained between 61 and 98% of variance when predicting snowboard performance. The test battery predicts better for women than for men and better for SBX, HP, and overall World Cup ranking than for the other disciplines. The results indicate that starting speed, leg power, core power, and aerobic capacity are important in different snowboarding events.

The role of a relative age effect in the first winter Youth Olympic Games in 2012

Background Owing to the separation into age groups at the first winter Youth Olympic Games (YOG), athletes differed in age by up to two years, leading to a potential relative age effect (RAE). Objective The purpose of this study was to define the role of the RAE in the first winter YOG with regard to sex, type of sport and performance. Methods The birth dates and anthropometric data of all 1021 athletes (557 male, 464 female, 14–19 years old) participating in 15 sports were analysed. A χ2 test was used to assess the difference between the observed and expected birth distributions. ANOVA (analysis of variance) and Kruskal−Wallis analyses were used to investigate differences in anthropometrics. Results The birth date distribution of the overall sample was significantly different from an equal distribution, with an over-representation of athletes born shortly after the cut-off date (χ2=284.7, p<0.001). A significant RAE was found in both male (χ2=245.1, p<0.001) and female competitors (χ2=74.6, p<0.001). An analysis based on the type of sport showed an RAE in all categories (strength—χ2=229.9, p<0.001, endurance—χ2=60.4, p<0.001 and technique-related sports χ2=25.2, p=0.001). Relatively older competitors were also over-represented among medal winners (χ2=47.9, p<0.001). Relatively older male competitors were significantly taller (p=0.005) and heavier (p<0.001) than younger competitors. No differences were found in female competitors. Conclusions The results suggest that relative age had a highly significant influence on participation in various sports regardless of sex. A possible strategy to reduce the RAE would be a fixed quota for each birth year within the two-year age group across events.

Comparisons of the ski turn techniques of experienced and intermediate skiers

We compared selected kinematic variables for four different ski turn techniques performed by five experienced and five intermediate male skiers. The four ski turn techniques were the upstem turn, the downstem turn, the parallel turn and the parallel step turn. Each turn was divided into the initiation phase and the first and second steering phases. Most of the statistically significant differences (P < 0.05) between the two groups were found for the initiation phases of the four turns. Both the hip axis-hand axis angle and the edging angle of the uphill ski were significantly different between the two groups for the upstem turn at the beginning of the initiation phase. For the downstem turn, significant differences between the groups were found at the start of the initiation phase for the hip axis-hand axis angle, the shoulder axis-fall line angle, and the edging angle of the uphill ski. The standard deviation of the distance between the tips of the two skis over the second steering phase also differed significantly between the two groups. For the parallel step turn, significant differences were found at the start of the initiation phase for the edging angle of the downhill ski and the downhill ski to movement direction angle. Significant differences were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. For the initiation phase of the parallel turn, significant differences were found for the timing of setting the ski pole, the uphill knee angle at the start of this phase and the range of the knee angle of the uphill leg from the start to the end of this phase. For this turn, significant differences between the two groups were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. One of the reasons it was possible to identify a few significant differences only for the turns analysed, was the variability within the intermediate group: for most of the variables analysed, the standard deviation was much higher for the intermediate than for the experienced group.

Performance-determining physiological factors in the luge start

Abstract In luge, the start is a performance-determining factor. Athletes spend several months in the off-season training to improve starting performance. The aim of this study was to evaluate the influence of different physiological factors on the luge start and identify an appropriate physiological test battery. Thirteen male members of the Austrian national luge team were recruited. All participants completed a test battery that consisted of tests for balance, jumping, isometric truck flexion and extension strength, leg strength, hand grip strength, isometric bench pull and bench press strength, flexibility, and a luge start simulator. Regression analyses of fitness variables and starting speeds revealed relationships (P at least 0.049) except for flexibility, isometric trunk flexion strength, and isometric leg strength at a knee angle of 100° (P at best 0.069). Results showed that a single variable (isometric bench pull strength) explained most of the variance in maximum push-off speed (R 2 = 0.750) and suggest that any test battery should include bench pull, trunk extension, and grip strength tests. Bench pull performance might also be a useful tool in the recruitment of athletes.